Potential application of bacteriophages in enrichment culture for improved prenatal streptococcus agalactiae screening

Jumpei Uchiyama, Hidehito Matsui, Hironobu Murakami, Shin Ichiro Kato, Naoki Watanabe, Tadahiro Nasukawa, Keijiro Mizukami, Masaya Ogata, Masahiro Sakaguchi, Shigenobu Matsuzaki, Hideaki Hanaki

Research output: Contribution to journalComment/debatepeer-review

6 Citations (Scopus)


Vertical transmission of Streptococcus agalactiae can cause neonatal infections. A culture test in the late stage of pregnancy is used to screen for the presence of maternal S. agalactiae for intrapartum antibiotic prophylaxis. For the test, a vaginal–rectal sample is recommended to be enriched, followed by bacterial identification. In some cases, Enterococcus faecalis overgrows in the enrichment culture. Consequently, the identification test yields false-negative results. Bacteriophages (phages) can be used as antimicrobial materials. Here, we explored the feasibility of using phages to minimize false-negative results in an experimental setting. Phage mixture was prepared using three phages that specifically infect E. faecalis: phiEF24C, phiEF17H, and phiM1EF22. The mixture inhibited the growth of 86.7% (26/30) of vaginal E. faecalis strains. The simple coculture of E. faecalis and S. agalactiae was used as an experimental enrichment model. Phage mixture treatment led to suppression of E. faecalis growth and facilitation of S. agalactiae growth. In addition, testing several sets of S. agalactiae and E. faecalis strains, the treatment with phage mixture in the enrichment improved S. agalactiae detection on chromogenic agar. Our results suggest that the phage mixture can be usefully employed in the S. agalactiae culture test to increase test accuracy.

Original languageEnglish
Article number552
Issue number10
Publication statusPublished - Oct 10 2018
Externally publishedYes


  • Culture enrichment
  • Enterococcus faecalis
  • Phage
  • Streptococcus agalactiae

ASJC Scopus subject areas

  • Infectious Diseases
  • Virology


Dive into the research topics of 'Potential application of bacteriophages in enrichment culture for improved prenatal streptococcus agalactiae screening'. Together they form a unique fingerprint.

Cite this